Prior art round balers generally have a bale forming chamber defined by an apron comprising an array of side-by-side belts, transverse slats extending between chains, a plurality of bale forming rolls or a combination of these various elements, e.g., bale forming rolls and side-by-side belts. The utilization of rolls in combination with belts is shown by way of example in the round baler of U.S. Pat. No. 4,870,812, issued Oct. 3, 1989 in the name of Richard E. Jennings, et al. In most balers the chamber defining elements, such as rolls and belts, are operatively mounted between the walls of a main frame as well as within the confines of a tail gate pivotally mounted to the main frame by coaxial pivot pins. In some balers the diameter of the chamber is fixed while in others the chamber expands as the size of the cylindrical package of crop material increases.
During field operation, a pickup assembly picks up crop material, such as hay, from the ground and feeds it into a fixed or expandable bale forming chamber where it is rolled up to form a compact cylindrical package of hay. While still inside the chamber the formed package is wrapped in its compact form by net, twine, or the like, after which the tailgate is pivoted open by hydraulic means, or the like, and the package is discharged as a completed bale onto the ground for subsequent handling. The tailgate is then closed whereupon the chamber is again ready for the formation of a similar subsequent package of crop material into a round bale.
It is common practice to use a latching assembly to maintain a round baler tailgate in the closed position during bale formation in the chamber. A good example of an arrangement of this type is shown on the front cover of New Holland Operator's Manual for Round Baler Model 630, No. 42063012, issued in 1992. The baler shown on page 3-1 of this manual also shows a latching assembly under conditions where the tailgate is open. Under certain crop conditions, prior art systems of this nature have caused excessive stress on the tailgate pivot pins when the hydraulic cylinder, employed to hold the latch in place during operation, exerts a force on the latch pin, which is applied as a rotational force on the tailgate pivot pins. Concurrently, a lateral force is incumbent on the tailgate during bale formation as the package of crop material expands within the chamber. Thus, the latch pin, which is being forced downwardly, transmits a downward force to the entire tailgate, which in turn produces the deleterious rotational force mentioned above, while at the same time a lateral force is being applied to the pivot pins, all of which could cause stress and ultimate fatigue if left uncorrected.